ADHD is an acronym for “attention deficit-hyperactivity disorder,” and is a type of behavioral disorder primarily seen in children. “Attention deficit disorder” or ADD was once classified as a separate condition, but is now considered a subtype of ADHD. Technically a neurobehavioral disorder, ADHD is characterized by restlessness, inattentiveness, difficulty concentrating, high levels of unfocused energy and impulsive behavior. Children with ADHD may also bore easily and have a hard time following instructions. The condition can also affect adults, and presents with similar symptoms. Stimulant drugs form the primary mode of treatment, as the vast majority of ADHD patients respond favorably.